December 17, 2024
3 read me
January 2025: History of science 50, 100 and 150 years ago
J particle; nitroglycerine engine
1925, Exercise in motion: “A few years before the invention of the motion picture, Mr. Eadweard Muybridge, at the University of Pennsylvania, used electrically timed cameras to study the precise movements of human muscles during exercise. Cross lines on the back were used to precisely measure each movement. Image is from plates copyrighted 1887 by Eadweard Muybridge.
American scientificthe volume 132, number 1; January 1925
1975
Thunder Crack or Thunder Rumble
“Lightning lasts only a few tenths of a second. Why does the resulting sound last half a minute or more? A typical lightning strike consists of three strokes along a channel about 10 kilometers long. Light from all parts of the channel reaches the observer almost immediately. The sound from different parts, however, reaches the observer at different times. If the lightning channel is generally at right angles to the line of sight, the sound will reach the observer almost simultaneously: a sudden, loud crack. If the channel is generally parallel to the line of sight, the farthest sound will reach the observer many seconds later than the nearest sound: a long hum.’
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The J Particle Quark can be Charmed
“The most surprising aspect of the discovery of a new subnuclear particle in two high-energy laboratories is the extremely long lifetime of the 10-particle.-20 the second This unexpected “slow” decay distinguishes the relatively massive new particle from the hundreds of other unstable subnuclear species that have been created with particle accelerators. Most of the latter particles have a lifetime of 10-23 the second The new particle is called the J particle by one group of experimenters and the psi particle by others. Another debated possibility is that the particle represents a “bound state” consisting of a “charmed” quark and its antiquark.”
1925
Does lactic acid cause muscle fatigue?
“What happens when we run out of breath or when we get exhausted? Dr. AV Hill, professor of physiology at University College London, recently discovered that there was a very close relationship between the fatigue caused by exercise and the production of a certain chemical called lactic acid in the muscles being used. Dr. Hill found that fatigue was accompanied by an increase in the amount of lactic acid in the muscles, and that recovery from fatigue was always accompanied by a decrease in lactic acid.’
Scientists dismissed the idea of lactic acid more than two decades ago, but it persists today. They suspect that inorganic phosphate causes skeletal muscle fatigue.
1875
The chromosphere covers the Sun
“The visible edge of the sun’s disk is surmounted at an altitude of between 8,000 and 10,000 miles by an envelope of rose-colored gases, which Mr. Norman Lockyer has named the chromosphere. Red flame covers the entire surface of the sun, and here and there it rises in cloud-like forms that rise to incredible heights. Spectroscopy has shown that the rising planes are nothing more than clouds of heated gas, mostly hydrogen. Their spectrum clearly shows the bright lines of that element, as well as another very prominent line. This hypothetical element has been named helium by Lockyer and Edward Frankland, though with doubtful propriety.”
Look for: Nitroglycerin engine
“M. Champion, a French chemist, the heat developed by a certain quantity of nitroglycerin in the explosion, when converted into motion, is capable of generating five times more energy than that produced by the explosion of the same quantity of gunpowder, and 3,000. times more than the combustion of the same amount of coal. One liter of nitroglycerin is confirmed to have a potential energy of 5,500 horsepower working for 10 hours. It remains to invent a machine that can take advantage of and control the enormous force.’
Monorail with Leather Brakes
“The Turkish Government have recently commenced the construction of a railway, called the Steam Caravan, between Alexandretta and Aleppo, Syria, a distance of 94.2 miles. A single rail is used, erected on a wall 28 inches high and 17.5 inches wide. Vehicles on the railway and on the wall The locomotives are equipped with leather-covered horizontal wheels, which rest against the sides of the masonry and serve as brakes, and the last cars of each train are similar It has arrangements. Each side of each carriage has two people, and the whole train is estimated to have 96 seats.”
